1. Field of the Invention
The present invention relates to technology for charging batteries of mobile communication terminals. More particularly, the present invention relates to a charging method and system, and a portable charging apparatus that can prevent a mobile communication terminal from determining that the portable charging apparatus connected to the mobile communication terminal is a Universal Serial Bus (USB) charging device, so that the mobile communication terminal does not enter a sleep mode.
2. Description of the Related Art
With an increase in development of information and communication technology and semiconductor technology, the use of various types of mobile communication terminals has increased. Mobile communication terminals utilize mobile convergence to provide additional service functions provided by other types of mobile communication terminals, as well as their traditional service functions. For example, mobile phones have additional functions as well as their usual communication functions such as a voice call, and message transmission and reception. Examples of the additional functions include a TeleVision (TV) viewing function (e.g., mobile broadcasting, such as Digital Multimedia Broadcasting (DMB), Digital Video Broadcasting (DVB), and the like), an audio playback function (e.g., Moving Pictures Expert Group (MPEG)-1 or MPEG-2 Audio Layer 3 (MP3)), a photographing function, an Internet access function, and the like. As mobile communication terminals provide a variety of functions described above, they face an issue of battery capacity related to their operation time. Since mobile communication terminals are small in size, they are limited in terms of increased battery capacity. In order to address this problem, charging methods have been implemented to employ a portable charging apparatus.
Mobile communication terminals of the related art have been adapted to use charging methods via a travel adapter and/or a Universal Serial Bus (USB) device. The mobile communication terminals of the related art can differentiate between charging modes using a travel adapter and a USB charging device by determining whether two data lines D+ and D− are connected to each other. For example, when a mobile communication terminal detects the connection of an external charging device, it determines whether two data lines D+ and D− are connected to each other. When the mobile communication terminal determines that two data lines D+ and D− are connected to each other, it concludes that it is connected to a travel adapter. On the contrary, when the mobile communication terminal determines that two data lines D+ and D− are not connected to each other, it concludes that it is connected to a USB charging device. Thereafter, the mobile communication terminal controls the charging of the battery.
The mobile communication terminals of the related art cannot identify whether an external charging device connected thereto is a portable charging apparatus. Therefore, when the mobile communication terminals of the related art connect with the portable charging apparatus, they detect that they are connected to a USB charging device and then control a charging process based on the USB charging device. When the mobile communication terminals ascertain that they are connected with a USB charging device instead of the portable charging apparatus, they also cannot enter a sleep mode. In this case, they continue to consume the electric power of their battery. In addition, since a maximum charging current, which will be effective if they had correctly detected that they are connected with the portable charging apparatus, is limited to a maximum current set according to the USB standard, the battery of the mobile communication terminal is charged at a reduced speed.